Federal Register: April 10, 2001 (Volume 66, Number 69)Rules and RegulationsPage 18554-18561From the Federal Register Online via GPO Access [wais.access.gpo.gov]

DOCID:fr10ap01-20

[Page 18554]

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

OPP-301114; FRL-6777-6RIN 2070-AB78

Imidacloprid; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

SUMMARY: This regulation establishes tolerances for combined residues of imidacloprid in or on edible podded beans, succulent shelled beans, turnip greens, cilantro, sweet corn, field corn, leaf petiole vegetable subgroup, and the citrus fruits group. The Interregional Research Project Number 4 (IR-4) and the Bayer Corporation requested these tolerances under the Federal Food, Drug, and Cosmetic Act, as amended by the Food Quality Protection Act of 1996.

DATES: This regulation is effective April 10, 2001. Objections and requests for hearings, identified by docket control number OPP-301114, must be received by EPA on or before June 11, 2001.

ADDRESSES: Written objections and hearing requests may be submitted by mail, in person, or by courier. Please follow the detailed instructions for each method as provided in Unit VI. of the SUPPLEMENTARY INFORMATION. To ensure proper receipt by EPA, your objections and hearing requests must identify docket control number OPP-301114 in the subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: Shaja R. Brothers, Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,Washington, DC 20460; telephone number: (703) 308-3194; and e-mail address: brothers.shaja@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

You may be affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer. Potentially affected categories and entities may include, but are not limited to:

Examples of Categories

NAICS codes

potentially affected entities

Industry

111

Crop production 112

Animal production 311

Food manufacturing 32532

Pesticide manufacturing

This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in the table could also be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether or not this action might apply to certain entities. If you have questions regarding the applicability of this action to a particular entity, consult the person listed under FOR FURTHER INFORMATION CONTACT.

B. How Can I Get Additional Information, Including Copies of this Document and Other Related Documents?

1. Electronically.You may obtain electronic copies of this document, and certain other related documents that might be available electronically, from the EPA Internet Home Page at http://www.epa.gov/. To access this document, on the Home Page select ``Laws and Regulations,'' ``Regulations and Proposed Rules,'' and then look up the entry for this document under the ``Federal Register--Environmental Documents.'' You can also go directly to the Federal Register listings at http://www.epa.gov/fedrgstr/. A frequently updated electronic version of 40 CFR part 180 is available at http://www.access.gpo.gov/ nara/cfr/cfrhtml_00/Title_40/40cfr180_00.html, a beta site currently under development.

2. In person. The Agency has established an official record for this action under docket control number OPP-301114. The official record consists of the documents specifically referenced in this action, and other information related to this action, including any information claimed as Confidential Business Information (CBI). This official record includes the documents that are physically located in the docket, as well as the documents that are referenced in those documents. The public version of the official record does not include any information claimed as CBI. The public version of the official record, which includes printed, paper versions of any electronic comments submitted during an applicable comment period is available for inspection in the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

II. Background and Statutory Findings

In the Federal Register of July 5, 2000 (65 FR 41455) (FRL-6590-6), and February 11, 2000 (65 FR 7008) (FRL-6487-9) EPA issued notices pursuant to section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a as amended by the Food Quality Protection Act of 1996 (FQPA) (Public Law 104-170) announcing the filing of pesticide petitions (PP) for tolerances by IR-4, Technology Centre of New Jersey, 681 US Highway #1 South, North Brunswick, NJ 08902-3390, and Bayer Corporation, 8400 Hawthorn Road, POB 4913, Kansas City, MO 64120-0013. These notices included summaries of these petitions prepared by Bayer Corporation, the registrant. There were no comments received in response to the notices of filing.

The petitions requested that 40 CFR 180.472 be amended by establishing tolerances for combined residues of the insecticide imidacloprid, [(1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2- imidazolidinimine) and its metabolites containing the 6-chloropyridinyl moiety, in or on the following commodities:

1. PP 0E6101 proposes the establishment of a tolerance for edible podded beans at 1.0 part per million (ppm).

2. PP 0E6104 proposes the establishment of a tolerance for succulent shelled beans at 1.0 ppm.

3. PP 0E6156 proposes the establishment of a tolerance for turnip greens at 3.5 ppm.

4. PP 9E6041 proposes the establishment of a tolerance for cilantro at 3.5 ppm.

5.PP 0E6106 proposes the establishment of tolerances for sweet corn grain at 0.05 ppm, sweet corn forage at 0.10 ppm, and sweet corn stover at 0.20 ppm.

6. PP 6F4682 proposes the establishment of tolerances for field corn grain at 0.05 ppm, field corn forage at 0.10 ppm, and field corn fodder at 0.20 ppm.

7. PP 8F4940 proposes the establishment of tolerances for leaf petiole vegetable subgroup at 6.0 ppm, citrus fruits group at 0.7 ppm, and citrus dried pulp at 5.0 ppm.

Section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a tolerance (the legal limit for a pesticide chemical residue in or on a food) only if EPA determines that the tolerance is ``safe.'' Section 408(b)(2)(A)(ii) defines ``safe'' to

[Page 18555]mean that ``there is a reasonable certainty that no harm will result from aggregate exposure to the pesticide chemical residue, including all anticipated dietary exposures and all other exposures for which there is reliable information.'' This includes exposure through drinking water and in residential settings, but does not include occupational exposure. Section 408(b)(2)(C) requires EPA to give special consideration to exposure of infants and children to the pesticide chemical residue in establishing a tolerance and to ``ensure that there is a reasonable certainty that no harm will result to infants and children from aggregate exposure to the pesticide chemical residue....''

EPA performs a number of analyses to determine the risks from aggregate exposure to pesticide residues. For further discussion of the regulatory requirements of section 408 and a complete description of the risk assessment process, see the final rule on Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).

III. Aggregate Risk Assessment and Determination of Safety

Consistent with section 408(b)(2)(D), EPA has reviewed the available scientific data and other relevant information in support of this action. EPA has sufficient data to assess the hazards of and to make a determination on aggregate exposure, consistent with section 408(b)(2), for tolerances for combined residues of imidacloprid on edible podded beans at 1.0 ppm, succulent shelled beans at 1.0 ppm, turnip greens at 3.5 ppm, cilantro at 3.5 ppm, sweet corn grain at 0.05 ppm, sweet corn forage at 0.10 ppm, sweet corn fodder at 0.20 ppm, field corn grain at 0.05 ppm, field corn forage at 0.10 ppm, field corn fodder at 0.20 ppm, leaf petiole vegetable subgroup at 6.0 ppm, citrus fruits group at 0.7 ppm, and citrus dried pulp at 5.0 ppm. EPA's assessment of exposures and risks associated with establishing these tolerances follow.

A. Toxicological Profile

EPA has evaluated the available toxicity data and considered its validity, completeness, and reliability as well as the relationship of the results of the studies to human risk. EPA has also considered available information concerning the variability of the sensitivities of major identifiable subgroups of consumers, including infants and children. The nature of the toxic effects caused by imidacloprid are discussed in Unit II. A. in the Federal Register of March 25, 1998 (FRL-5776-5).

B. Toxicological Endpoints

The dose at which no adverse effects are observed (the NOAEL) from the toxicology study identified as appropriate for use in risk assessment is used to estimate the toxicological level of concern (LOC). However, the lowest dose at which adverse effects of concern are identified (the LOAEL) is sometimes used for risk assessment if no NOAEL was achieved in the toxicology study selected. An uncertainty factor (UF) is applied to reflect uncertainties inherent in the extrapolation from laboratory animal data to humans and in the variations in sensitivity among members of the human population as well as other unknowns. An UF of 100 is routinely used, 10x to account for interspecies differences and 10x for intraspecies differences.

For dietary risk assessment (other than cancer) the Agency uses the UF to calculate an acute or chronic reference dose (acute RfD or chronic RfD) where the RfD is equal to the NOAEL divided by the appropriate UF (RfD = NOAEL/UF). Where an additional safety factor is retained due to concerns unique to the FQPA, this additional factor is applied to the RfD by dividing the RfD by such additional factor. The acute or chronic Population Adjusted Dose (aPAD or cPAD) is a modification of the RfD to accommodate this type of FQPA Safety Factor.

For non-dietary risk assessments (other than cancer) the UF is used to determine the LOC. For example, when 100 is the appropriate UF (10x to account for interspecies differences and 10x for intraspecies differences) the LOC is 100. To estimate risk, a ratio of the NOAEL to exposures (margin of exposure (MOE) = NOAEL/exposure) is calculated and compared to the LOC.

The linear default risk methodology (Q*) is the primary method currently used by the Agency to quantify carcinogenic risk. The Q* approach assumes that any amount of exposure will lead to some degree of cancer risk. A Q* is calculated and used to estimate risk which represents a probability of occurrence of additional cancer cases (e.g., risk is expressed as 1 x 10-6or one in a million). Under certain specific circumstances, MOE calculations will be used for the carcinogenic risk assessment. In this non-linear approach, a ``point of departure'' is identified below which carcinogenic effects are not expected. The point of departure is typically a NOAEL based on an endpoint related to cancer effects though it may be a different value derived from the dose response curve. To estimate risk, a ratio of the point of departure to exposure (MOE cancer= point of departure/exposures) is calculated. A summary of the toxicological endpoints for imidacloprid used for human risk assessment is shown in the following Table 1:

Table 1.--Summary of Toxicological Dose and Endpoints for Imidacloprid for Use in Human Risk Assessment

FQPA SF* and Level of Exposure Scenario

Dose Used in Risk

Concern for Risk Study and Toxicological Assessment, UF

Assessment

Effects

Acute Dietary general population (NOAEL was not

FQPA SF = 3X aPAD = Acute RfD = 0.42 mg/kg including infants and children

established) LOAEL = acute RfD FQPA SF = bwt/day LOAEL = 42 mg/ 42 mg/kg/day UF = 100 0.14 mg/kg/day

kg bwt/day based on Acute RfD = 0.42 mg/kg/

decreased motor day

activity in female rats; additional 3x FQPA factor for all population subgroups to account for neurotoxicity, structure-activity concerns and lack of a NOAEL.

aPAD = RfD /3 = 0.14 mg/ kg bwt/day.

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Chronic Dietary all populations

NOAEL= 5.7 mg/kg/day UF FQPA SF = 3X cPAD = Chronic RfD = 0.057 mg/ = 100 Chronic RfD = chronic RfD FQPA SF = kg bwt/day; NOAEL = 0.057 mg/kg/day

0.019 mg/kg/day

5.7 mg/kg bwt/day based on increased number of thyroid lesions at the LOAEL of 16.9/24.9 mg/kg bwt/ day (males and females, respectively); additional 3x FQPA factor for all population subgroups.

Short-Intermediate-Long Term Dermal N/A

N/A

Dermal endpoints were notidentified due to demonstratedabsence of toxicity.

(Residential)

Short-Intermediate-Long Term

N/A

N/A

Inhalation endpoints Inhalation

were notidentified due to demonstratedabsence of toxicity.

(Residential)

Cancer (oral, dermal, inhalation) N/A

N/A

No evidence of carcinogenicity.

*The reference to the FQPA Safety Factor refers to any additional safety factor retained due to concerns unique to the FQPA.

C. Exposure Assessment

1. Dietary exposure from food and feed uses. Tolerances have been established (40 CFR 180.472) for the combined residues of imidacloprid and its metabolites containing the 6-chloropyridinyl moiety, all expressed as parent, in or on a variety of raw agricultural commodities. Tolerances, which also include time-limited tolerances, have also been established in or on a variety of raw agricultural and animal commodities at levels ranging from 0.02 ppm in eggs to 15 ppm in raisins, waste. Risk assessments were conducted by EPA to assess dietary exposures from imidacloprid in food as follows:

i. Acute exposure. Acute dietary risk assessments are performed for a food-use pesticide if a toxicological study has indicated the possibility of an effect of concern occurring as a result of a 1 day or single exposure. The Dietary Exposure Evaluation Model (DEEM) analysis evaluated the individual food consumption as reported by respondents in the USDA 1989-1992 nationwide Continuing Surveys of Food Intake by Individuals (CSFII) and accumulated exposure to the chemical for each commodity. The following assumption was made for the acute exposure assessment: Tolerance level residues for imidacloprid were used, and a Tier 1 analysis for 100% crop-treated.

ii. Chronic exposure. In conducting this chronic dietary risk assessment the DEEM analysis evaluated the individual food consumption as reported by respondents in the USDA 1989-1992- nationwide CSFII and accumulated exposure to the chemical for each commodity. The following assumptions were made for the chronic exposure assessment: Tolerance level residues for imidacloprid were used, and percent crop-treated information for some crops.

iii. Cancer. Imidacloprid has been classified as a Group E chemical, no evidence of carcinogenicity for humans. Therefore, a cancer risk assessment was not conducted.

iv. Anticipated residue and percent crop treated information. Section 408(b)(2)(F) states that the Agency may use data on the actual percent of food treated for assessing chronic dietary risk only if the Agency can make the following findings: Condition (1), that the data used are reliable and provide a valid basis to show what percentage of the food derived from such crop is likely to contain such pesticide residue; Condition (2), that the exposure estimate does not underestimate exposure for any significant subpopulation group; and Condition (3), if data are available on pesticide use and food consumption in a particular area, the exposure estimate does not understate exposure for the population in such area. In addition, the Agency must provide for periodic evaluation of any estimates used. To provide for the periodic evaluation of the estimate of percent crop treated (PCT) as required by section 408(b)(2)(F), EPA may require registrants to submit data on PCT.

The Agency used percent crop treated (PCT) information as follows:

The Agency used PCT information to conduct a routine chronic dietary exposure analysis for imidacloprid based on likely maximum percent crop treated as follows: 19% apples, 21% brassica leafy vegetables, 15% christophine, 15% crenshaws, 15% melons, 15% watermelon, 15% wintermelon, 13% citrus citron, 6% cotton, 30% eggplant, 6% grapefruit, 11% grapes, 13% kumquats, 13% lemons, 32% lettuce-head varieties, 13% limes, 3% oranges, 30% paprika, 2% pears, 3% peppers, 13% tangelos, 13% tangerines, and 10% tomatoes. Other commodities were assumed to be 100% treated.

The Agency believes that the three conditions listed above have been met. With respect to Condition 1, PCT estimates are derived from Federal and private market survey data, which are reliable and have a valid basis. EPA uses a weighted average PCT for chronic dietary exposure estimates. This weighted average PCT figure is derived by averaging State-level data for a period of up to 10 years, and weighting for the more robust and recent data. A weighted average of the PCT reasonably represents a person's dietary exposure over a lifetime, and is unlikely to underestimate exposure to an individual because of the fact that pesticide use patterns (both regionally and nationally) tend to change continuously over time, such that an individual is unlikely to be exposed to more than the average PCT over a lifetime. For acute dietary exposure estimates, EPA uses an estimated maximum PCT. The exposure estimates resulting from this approach reasonably represent the highest levels to which an individual could be exposed, and are unlikely to underestimate an individual's acute

[Page 18557]dietary exposure. The Agency is reasonably certain that the percentage of the food treated is not likely to be an underestimation. As to Conditions 2 and 3, regional consumption information and consumption information for significant subpopulations is taken into account through EPA's computer-based model for evaluating the exposure of significant subpopulations including several regional groups. Use of this consumption information in EPA's risk assessment process ensures that EPA's exposure estimate does not understate exposure for any significant subpopulation group and allows the Agency to be reasonably certain that no regional population is exposed to residue levels higher than those estimated by the Agency. Other than the data available through national food consumption surveys, EPA does not have available information on the regional consumption of food to which imidacloprid may be applied in a particular area.

2. Dietary exposure from drinking water. Imidacloprid is persistent, water soluble, and fairly mobile. Thus, residues of imidacloprid may be transported to both surface and ground waters. As a condition of registration, the Agency is requiring the submission of the results of two prospective ground water monitoring studies. Results from these studies are not yet available. However, estimates of imidacloprid's residue concentration in surface and ground waters has been provided by EPA water models.

The Agency lacks sufficient monitoring exposure data to complete a comprehensive dietary exposure analysis and risk assessment for imidacloprid in drinking water. Because the Agency does not have comprehensive monitoring data, drinking water concentration estimates are made by reliance on simulation or modeling taking into account data on the physical characteristics of imidacloprid.

The Agency uses the Generic Estimated Environmental Concentration (GENEEC) or the Pesticide Root Zone/Exposure Analysis Modeling System (PRZM/EXAMS) to estimate pesticide concentrations in surface water and Screening Concentration in Ground Water (SCI-GROW), which predicts pesticide concentrations in ground water. In general, EPA will use GENEEC (a tier 1 model) before using PRZM/EXAMS (a tier 2 model) for a screening-level assessment for surface water. The GENEEC model is a subset of the PRZM/EXAMS model that uses a specific high-end runoff scenario for pesticides. GENEEC incorporates a farm pond scenario, while PRZM/EXAMS incorporate an index reservoir environment in place of the previous pond scenario. The PRZM/EXAMS model includes a percent crop area factor as an adjustment to account for the maximum percent crop coverage within a water shed or drainage basin.

None of these models include consideration of the impact processing (mixing, dilution, or treatment) of raw water for distribution as drinking water would likely have on the removal of pesticides from the source water. The primary use of these models by the Agency at this stage is to provide a coarse screen for sorting out pesticides for which it is highly unlikely that drinking water concentrations would ever exceed human health levels of concern.

Since the models used are considered to be screening tools in the risk assessment process, the Agency does not use estimated environmental concentrations (EECs) from these models to quantify drinking water exposure and risk as a %RfD or %PAD. Instead drinking water levels of comparison (DWLOCs) are calculated and used as a point of comparison against the model estimates of a pesticide's concentration in water. DWLOCs are theoretical upper limits on a pesticide's concentration in drinking water in light of total aggregate exposure to a pesticide in food, and from residential uses. Since DWLOCs address total aggregate exposure to imidacloprid they are further discussed in the aggregate risk sections below.

Based on the GENEEC and SCI-GROW models the EECs of imidacloprid for acute exposures are estimated to be 17.4 parts per billion (ppb) for surface water and 1.4 ppb for ground water. The EECs for chronic exposures are estimated to be 15.8 ppb for surface water and 1.4 ppb for ground water.

3. From non-dietary exposure. The term ``residential exposure'' is used in this document to refer to non-occupational, non-dietary exposure (e.g., for lawn and garden pest control, indoor pest control, termiticides, and flea and tick control on pets).

Imidacloprid is currently registered for use on the following residential non-dietary sites: Turf, home garden and pet uses. Dermal and inhalation short- and intermediate-term risk assessments were not conducted for imidacloprid as dermal and inhalation exposure endpoints were not identified due to the demonstrated absence of toxicity. Short- and intermediate term oral exposures are not expected for adult population subgroups. A short-term aggregate risk assessment is required for hand-to-mouth (oral) exposure for children. The risk assessment was conducted using the following residential exposure assumptions: (oral exposure) hand to mouth exposure for children from home garden, turf, and pet uses.

4. Cumulative exposure to substances with a common mechanism of toxicity. Section 408(b)(2)(D)(v) requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider ``available information'' concerning the cumulative effects of a particular pesticide's residues and ``other substances that have a common mechanism of toxicity.''

EPA does not have, at this time, available data to determine whether imidacloprid has a common mechanism of toxicity with other substances or how to include this pesticide in a cumulative risk assessment. Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, imidacloprid does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has not assumed that imidacloprid has a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the final rule for Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997).

D. Safety Factor for Infants and Children

1. In general. FFDCA section 408 provides that EPA shall apply an additional tenfold margin of safety for infants and children in the case of threshold effects to account for prenatal and postnatal toxicity and the completeness of the data base on toxicity and exposure unless EPA determines that a different margin of safety will be safe for infants and children. Margins of safety are incorporated into EPA risk assessments either directly through use of a margin of exposure (MOE) analysis or through using uncertainty (safety) factors in calculating a dose level that poses no appreciable risk to humans.

2. Prenatal and postnatal sensitivity. In assessing the potential for additional sensitivity of infants and children to residues of imidacloprid, EPA considered data from developmental toxicity studies in the rat and rabbit and a 2-generation reproduction study in the rat (Federal Register September 18, 1998, Unit II. A.). The developmental toxicity data demonstrated no increased

[Page 18558]sensitivity of rats or rabbits to in utero exposure to imidacloprid. In addition, the multi-generation reproductive toxicity study did not identify any increased sensitivity of rats to in utero or postnatal exposure.

3. Conclusion. Based on the clinical signs of neurological toxicity in the acute toxicity studies and the requirement for a developmental neurotoxicity study, EPA concluded that a FQPA safety factor of 3x is appropriate for this risk assessment. The safety factor of 10x was reduced to 3x because there was no qualitative or quantitative evidence of increased susceptibility of fetuses or offspring exposed to imidacloprid in the prenatal developmental toxicity studies in rats and rabbits, or in the 2-generation reproduction toxicity study in rats.

E. Aggregate Risks and Determination of Safety

To estimate total aggregate exposure to a pesticide from food, drinking water, and residential uses, the Agency calculates DWLOCs which are used as a point of comparison against the model estimates of a pesticide's concentration in water (EECs). DWLOC values are not regulatory standards for drinking water. DWLOCs are theoretical upper limits on a pesticide's concentration in drinking water in light of total aggregate exposure to a pesticide in food and residential uses. In calculating a DWLOC, the Agency determines how much of the acceptable exposure (i.e., the PAD) is available for exposure through drinking water e.g., allowable chronic water exposure (mg/kg/day) = cPAD - (average food + residential exposure). This allowable exposure through drinking water is used to calculate a DWLOC.

A DWLOC will vary depending on the toxic endpoint, drinking water consumption, and body weights. Default body weights and consumption values as used by the USEPA Office of Water are used to calculate DWLOCs: 2L/70 kg (adult male), 2L/60 kg (adult female), and 1L/10 kg (child). Default body weights and drinking water consumption values vary on an individual basis. This variation will be taken into account in more refined screening-level and quantitative drinking water exposure assessments. Different populations will have different DWLOCs. Generally, a DWLOC is calculated for each type of risk assessment used: Acute, short-term, intermediate-term, chronic, and cancer.

When EECs for surface water and groundwater are less than the calculated DWLOCs, OPP concludes with reasonable certainty that exposures to the pesticide in drinking water (when considered along with other sources of exposure for which OPP has reliable data) would not result in unacceptable levels of aggregate human health risk at this time. Because OPP considers the aggregate risk resulting from multiple exposure pathways associated with a pesticide's uses, levels of comparison in drinking water may vary as those uses change. If new uses are added in the future, OPP will reassess the potential impacts of residues of the pesticide in drinking water as a part of the aggregate risk assessment process.

1. Acute risk. Using the exposure assumptions discussed in this unit for acute exposure, the acute dietary exposure from food to imidacloprid will occupy 23% of the aPAD for the U.S. population, 18% of the aPAD for females 13 years and older, 35% of the aPAD for all infants 01-8805Filed4-9-01; 8:45 am] BILLING CODE 6560-50-S